The present invention relates generally to telecommunications, and more particularly to the utilization of underutilized communication channels as outbound gateways.
The public switched telephone network (PSTN) has provided reliable voice and data communication for many years. As is well known, the PSTN is a circuit switched network in which a call from a calling terminal to a called terminal creates a dedicated circuit between the two terminals. The circuit carries voice or data signals between the two terminals. For many years, the PSTN has been the primary form of telephony communication. Most homes and businesses today have at least one connection to the PSTN. The physical connection from a customer premises to the PSTN is referred to as the local loop. Most commonly, the local loop comprises twisted pair copper wire between the customer premises and the central office (CO) of a local exchange carrier (LEC). The twisted pair generally provides analog telephone service, but in some installations provide for high bandwidth communications via a digital subscriber line (DSL).
More recently, customer premises are also connected to other types of high bandwidth communication networks. For example, many homes have a connection to a cable television network, which is generally implemented using coaxial cable, optical fiber, or a combination of the two (e.g. hybrid fiber-coax (HFC)). Originally, the cable television network was used for downstream communications from a cable head end to the customer premises. More recently, such networks have been modified to provide bi-directional data transport in both the downstream and upstream directions.
The increase in connectivity to high bandwidth data networks has also led to the provisioning of new services over such networks. For example, telephony service is now available via a high bandwidth data connection (e.g., via the Internet) using voice-over-Internet-Protocol (VoIP). The VoIP protocol transmits encoded voice as data packets via a high bandwidth data network. The voice data is encoded and decoded at the endpoints (or at some intermediate network location) so that a voice conversation between two telephones may take place.
Since many customer premises now have connections to multiple networks, with one such network often being a high bandwidth network, there is often unused bandwidth between the customer premises and the one or more external networks. One use for such unused bandwidth is described in U.S. Pat. No. 6,738,470 (the “'470 patent”), which describes a technique for using one subscriber's DSL connection to route a digital telephone call to a PSTN phone without using a central office gateway to convert the call from the digital domain to the analog domain. The subscriber whose DSL connection is used as the gateway is called a “pass-through” subscriber, as the telephone call is passed through that subscriber's premises and equipment, but does not terminate there. In effect, this system uses unused bandwidth of a subscriber in order to utilize equipment at the customer premises as a gateway. One of the advantages of such a system, as described in the '470 patent, is that it avoids the cost of processing by a central gateway (e.g., the local telephone company). Thus, rather than utilizing a central gateway for processing a call, and paying for such processing, processing may be performed at a customer premises, thereby avoiding the cost of central gateway processing.